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Department of Veterinary Medicine

Cambridge Veterinary School

Intervertebral disc disease in dogs

Thoracolumbar intervertebral disc herniation (TL IVDH) is known to have a lifetime prevalence of ~20% in the Miniature Dachshund, and is fatal in 25% of cases. There is a perception that dogs which are more severely affected require decompressive surgery to recover ambulation, and a small amount of evidence to support this. The severe clinical signs are distressing to owners and further compounded by high financial costs of cross sectional imaging and surgery. It is however known that some dogs will recover without the need for surgery, and in 2017 I carried out an extensive data mining exercise which showed that recovery rates of  dogs suffering from TL IVDH treated with medical therapy are similar to those following surgical management in all grades of severity except the most severely affected dogs (Freeman and Jeffery, JSAP 2017: 58, 199-204).

My PhD student is studying dogs rendered non-ambulatory following acute TL IVDH and treated medically rather than surgically; these dogs receive an MRI scan to confirm diagnosis, followed by a second scan after three months of medical management. It is known that in some cases both in human and canine disc herniation the herniated material is removed by natural processes (Argent et al 2019) and we aim to document the frequency with which this occurs, and whether there is a correlation with recovery of ambulation. 

We aim to provide answers to a number of questions:

  • Can dogs rendered non-ambulatory following acute compressive thoracolumbar intervertebral disc herniation (TL IVDH) recover ambulation without decompressive surgery?
  • By what mechanism may herniated intervertebral disc material be removed by natural processes from the vertebral canal in dogs treated conservatively for TL IVDH?
  • Is recovery of ambulation and/or speed of recovery associated with removal of extruded disc material from the vertebral canal?

Ultimately we aim to provide an answer to the key question: In dogs suffering acute severe TL IVDH, which cases genuinely require surgical treatment, and which may recover just as well with medical management

There are many other unanswered questions surrounding the role of calcification in the pathogenesis of intervertebral disc extrusion in dogs as well as humans.

Some of the key questions we have are:

  • Why do certain specific discs tend to extrude commonly, whereas others rarely do?
  • Why do some extrusions cause calamitous irreversible spinal cord injury, whereas others only lead to minimal self-limiting pain?
  • Why should disc calcification lead to an increased risk of disc extrusion?

Additional work being carried out currently by my MPhil student with the assistance of Jonathan Powell’s biominerals laboratory and Professor Rachel Oliver from the Dept of Materials Science and Metallurgy is aimed at identifying the role of calcification in IVDH. Several studies have attempted to investigate the role of calcification in human disc herniation (Grant et al 2016, Shao et al 2016), and we have begun to look more closely into the mineral analysis of extruded and non-extruded disc material. Our early results indicate, as expected, a very high level of calcium and phosphorous in extruded disc material removed from the vertebral canal of clinical cases, and we have now been able to establish the nature of this calcified material in both extruded and non-extruded discs. We are now attempting to determine biomechanical features of this material on a nanoscale using atomic force microscopy.

We aim compare calcification in extruded and non-extruded disc material,as well as in non-degenerate discs, looking for reasons why some discs extrude and others do not, and why some extrusions are so catastrophic but others relatively benign.

Finally we are involved in a newly launched Kennel Club screening scheme for Dachshunds which provides guidelines for breeding based on the numbers of calcified discs identified by radiography. We are able to offer a CT scan alongside the radiographs, a much more sensitive modality for identification of disc calcification, with the aim of following these dogs and assessing their likelihood of suffering IVDH later in life.

In addition to this work, I am collaborating with the work of bioengineer George Malliaras and Christopher Proctor, who have designed an electrical stimulation device intended to deliver an oscillating electrical field to injured spinal cord. Our aim is to implant a series of such devices onto the surface of the injured spinal cord in a series of dogs suffering acute severe injury as a result of intervertebral disc disease.This type of stimulation has been shown in both dogs and humans to improve recovery in severe spinal cord injury, but currently no commercially available stimulator is in use. This technology has the potential to improve outcomes in both dogs and people suffering severe spinal cord injury.


Paul graduated from Cambridge in 1987 and then spent 6 years in mixed practice in Yorkshire and Suffolk. In 1993 he gained the RCVS certificate in small animal orthopaedics, and went on to develop a referral centre for orthopaedics and neurology in his home county of Essex.

Paul gained the European Diploma in Veterinary Neurology in 2014, and in 2016 took up his current post of Principal Clinical Neurologist at the Queen's Veterinary School Hospital in the Department of Veterinary Medicine. The neurology service has grown rapidly over the last few years, and currently employs 3 specialist neurologists as well as a resident in training and service intern. Paul's main areas of interest continue to be in the management of canine spinal cord injury specifically intervertebral disc disease, and he has published review articles in 2017 and 2018 on the role of intervertebral disc fenestration. Despite having a mainly clinical role, Paul manages to combine research and teaching interests with the steadily increasing clinical caseload at QVSH.

Paul has lectured widely both nationally and internationally, and greatly enjoys the teaching aspect of his current role and involvement with veterinary students and residents, as well as working within an experienced team of specialists.  


My research is focused on intervertebral disc disease in dogs. Currently I have a PhD student, Sam Khan, funded jointly by the Kennel Club Charitable Trust (KCCT), BSAVA Petsavers, Debs Foundation and Dachshund Health UK. Sam's work is based on following the natural progression of the disease through imaging.

I also have an MPhil student, Viviana Rojas, fully funded by Dachshund rescue UK. Viviana is following on from a previous MPhil student Theresa Banu Yenen, investigating the mineral content of intervertebral discs and its role in the pathology of the disease.

Sam is co-supervised by my colleague from the pathology department Kate Hughes, whilst Viviana is co-supervised by my neurologist colleague Lisa Alves. 


Key publications: 

Longo, S., Gomes, S. A., Briola, C., Duffy, K., Targett, M., Jeffery, N. D., & Freeman, P. (2021). Association of magnetic resonance assessed disc degeneration and late clinical recurrence in dogs treated surgically for thoracolumbar intervertebral disc extrusions. Journal of veterinary internal medicine35(1), 378–387.

Fox K, Fox J, Bexfield N, Freeman P. Computerised decision support in veterinary medicine, exemplified in a canine idiopathic epilepsy care pathway. J Small Anim Pract. 2021 Oct;62(10):911-917. doi: 10.1111/jsap.13345. Epub 2021 Jun 21. PMID: 34155645.

Hall JF, Freeman P. Approach to and Practice of Disc Fenestration in the Management of Intervertebral Disc Extrusions in Dogs: A Questionnaire Survey. Vet Comp Orthop Traumatol. 2021 Aug 3. doi: 10.1055/s-0041-1731809. Epub ahead of print. PMID: 34344052.

Freeman P, Jeffery ND. Re-opening the window on fenestration as a treatment for acute thoracolumbar intervertebral disc herniation in dogs. J Small Anim Pract. 2017 Apr;58(4):199-204. doi: 10.1111/jsap.12653. PMID: 28276121.

Jeffery ND, Freeman PM. The Role of Fenestration in Management of Type I Thoracolumbar Disk Degeneration. Vet Clin North Am Small Anim Pract. 2018 Jan;48(1):187-200. doi: 10.1016/j.cvsm.2017.08.012. Epub 2017 Oct 23. PMID: 29074336.

Harris G, Freeman P. Introduction of Disc Material into the Vertebral Canal by Fenestration of Thoracolumbar Discs Following Decompressive Surgery. Vet Comp Orthop Traumatol. 2020 Jan;33(1):66-70. doi: 10.1055/s-0039-1700554. Epub 2019 Nov 22. PMID: 31756749.

Hare C, Sanchini L, Worrall C, Van Poucke S, Alves L, Restif O, Freeman P. Rapid in-house method of CSF analysis utilising sedimentation direct from the spinal needle. J Small Anim Pract. 2019 Aug;60(8):486-492. doi: 10.1111/jsap.13010. Epub 2019 Apr 26. PMID: 31025384.

Freeman PM, Holmes MA, Jeffrey ND, Granger N. Time requirement and effect on owners of home-based management of dogs with severe chronic spinal cord injury.  Journal of Veterinary Behavior (2013), 8(6): 439-443

Other publications: 

Monforte Monteiro SR et al, “Medical management of spinal epidural empyema in five dogs”. Journal of the American Veterinary Medicine Association (2017) 249, 10: 1180-1186.

Cashmore RG, Harcourt-Brown TR, Freeman PM, Jeffery ND, Granger N. Clinical diagnosis and treatment of suspected neuropathic pain in three dogs. Australian Veterinary Journal (2009), 87(1): 45-50.

Serrano G, Freeman P. Neosporosis presenting as temporal muscle atrophy in a dog. Veterinary Record Case Reports Mar 2017, 5 (1) e000380; DOI: 10.1136/vetreccr-2016-000380

Kortum A, Freeman P. Fibrocartilaginous embolism and marked cerebrospinal fluid pleocytosis in a dog. Veterinary Record Case Reports May 2018, 6 (2) e000608; DOI: 10.1136/vetreccr-2018-000608

Argent V, Fraser A, Alves L, Freeman P. Spontaneous regression of a cervical intervertebral disc extrusion in French bulldogs documented on MRI after medical management. Veterinary Record Case Reports Apr 2019, 7 (2) e000817; DOI: 10.1136/vetreccr-2019-000817

Clarke N, Harris G, Greville-Heygate O,Constantino-Casas F, Freeman P. Spinal cord clear cell meningioma in a dog. Veterinary Record Case Reports Jul 2020, 8 (3) e001118; DOI: 10.1136/vetreccr-2020-001118

Freeman P. Sacrococcygeal intervertebral disc extrusion in a Dachshund. Veterinary Record (2010), 167(16): 618-9

Freeman PM, Harcourt-Brown TR, Jeffery ND, Granger N. Electrophysiologic evidence of polyneuropathy in a cat with signs of bilateral brachial plexus neuropathy. J Am Vet Med Assoc. 2009 Jan 15;234(2):240-4. doi: 10.2460/javma.234.2.240. PMID: 19210244.

Teaching and Supervisions


Neurology module organiser, Cambridge University Veterinary School

Research supervision: 

Sam Khan (PhD)

Viviana Rojas (MPhil)

Other Professional Activities

Principal Clinical Neurologist at Queen's Veterinary School Hospital

Principal Clinical Neurologist
European & RCVS Specialist in Veterinary Neurology
Takes PhD students
Available for consultancy


Person keywords: 
Disc disease
Veterinary Education
The Alice Noakes Trust
The Debs Foundation
BSAVA Petsavers
Dachshund Health UK
Dachshund Rescue UK
Kennel Club Charitable Trust